It is customary to treat animals to control and/or avoid insects and pest infestation, particularly fleas and ticks, by spraying the coats of the animals with, or dipping the animals in, an insecticide solution. This type of treatment provides temporary protection, usually lasting about three weeks. After this time period, the treatment may be degraded by light and microorganisms so that its effectiveness decreases.
Other types of insect and pest controls are also known. For example, insecticidal ear tags have recently become a valuable tool for the control of livestock pests. The ear tags release an insecticide, which is spread when the tag rubs against an animal's coat. U.S. Pat. No. 4,606,478 describes such an ear tag, which has a reservoir containing a liquid pesticide. Liquid pesticides are generally undesirable for use in collars, as they can easily be chewed through, releasing the liquid pesticide.
Further, for domesticated pets, such as dogs and cats, collars containing an insecticidal composition have been used to protect these animals against fleas and ticks. However, the protection offered by such collars is unreliable. See, e.g. the device described in U.S. Pat. No. 4,930,451. These collars are also short-lived because the matrix used is a solid, which provides poor efficiency in distribution of the insecticide.
There remains a need in the art for an effective device for protecting animals against ticks and fleas for an extended period of time.